The present invention relates to the art of liquid fuel-fired water heating tanks and, more particularly, to a down-fired water heating tank.
Liquid fuel-fired water heating tanks are of course well known, and it is likewise well known that certain such water heating tanks heretofore provided include an annular upright water receptacle having a vertical exhaust flue or passageway centrally therethrough, a combustion chamber beneath the receptacle, and communicating with the central exhaust flue, and a liquid fuel-fired burner unit radially associated with the combustion chamber and having a burner tube opening radially thereinto. During operation, a fuel-air mixture is ignited and burns in the combustion chamber to heat water in the receptacle, which heating is supplemented by the flow of hot exhaust gases upwardly through the exhaust flue to an external exhaust duct. The location of the combustion chamber at the bottom of the water receptacle, however, results in considerable loss of usable heat by the flow of hot gasses upwardly through the exhaust flue. Therefore, the heating efficiency is lower than is desired with respect to heating water in the receptacle, whereby more fuel is required to achieve heating of the water and maintenance of the heat thereof at a given temperature. In this respect, it will be appreciated that the burner has to operate for longer periods of time to achieve and maintain desired water temperature levels. Such frequent and extended burner operation not only effects the cost of operating the water heating tank, but also the life of the component parts of the burner assembly and combustion chamber, and thus maintenance costs with respect to the water heating tank.
The burner unit of such bottom fired water heating tanks is removably mounted on the lower outer portion of the housing or jacket of the tank to facilitate removal of the burner unit for maintenance purposes with respect thereto and with respect to the combustion chamber. Removal of the burner unit provides access to the combustion chamber through the burner tube opening, but such access is not convenient for maintenance personnel because of the small size of the opening and the location thereof close to the floor. In this respect, maintenance operations, such as replacement of combustion chamber liners, necessitate reaching into the combustion chamber which is physically difficult and uncomfortable for maintenance personnel. Further, any effort to visually inspect the interior of the combustion chamber is not only limited by the size of the burner tube opening through the housing, but practically requires maintenance personnel to lie on the floor in order to look into the opening. Thus, maintenance operations are time consuming and tedious and at best are limited with respect to a desired thoroughness.